Heat-treating apparatus



May 19, 1953 J. A. Dow 2,639,138

l HEAT-TREATING APPARATUS Filed oct'. 28. 1947 3 sheets-sheet 1 l JNVENTOR. JOHN A. Dow

4 TTORNEV May 19, 1953 J. A. Dow 2,639,138

HEAT-TREATING APPARATUS Filed Oct. 28, 194'? 3 Sheets-Sheet 2 I |4 INVENTOR. :ELE-Ir: JoHN A. Dow

ATTORNEY 3 Sheets-Sheet I5 Filed Oct. 28, 1947 INVENTOR. JoHN A. Dow

TOR/VEP Patented May 19, 1953 HEAT-TREATING APPARATUS John A. Dow, Huntington Woods, Mich.; Doris B.

Dow, administratrix of said John A. Dow, deceased, assignor to Doris B. Dow, Royal Oak,

Mich., as trustee Application October 28, 1947, Serial No. 782,647

(Cl. 26S-4) 4 Claims.

This invention relates to the art of heat treating metals and has particular relationto furnace apparatus employed in this art, equipped with conveyer, quenching and other mechanisms, all operatively associated and rela'ted in such manner as to improve and to simplify the practices employed in the art and to reduce the cost of operation thereof,

An object of the invention is to provide a heat treating furnace apparatus in which conveyer means is employed within the furnace for facilitating the handling of work to be processed in the furnace and for making the furnace more easily and efficiently related to other equipment which the process of heat treating may require.

Another object of the invention is to provide a quenching apparatus adaptable for association with heat treating furnaces in such manner that the whole apparatus can be eficiently utilized in the heat treating process.

Another object of the invention is to provide an improved quenching apparatus in which work can be more efliciently and qualitatively processed than in quenching apparatus heretofore employed for such purposes.

Another object of the invention is to provide a heat treating furnace apparatus with various auxiliary apparatus by which the heat treating process may be made more flexible and eicient with respect to various requirements for heat treating placed upon all of such aparatus than has heretofore been capable of realization.

Another object of the invention is to provide a construction and arrangement of the ypartsof a heat treating furnace mechanism whereby such parts of the furnace which may'require service may be more expeditiously removed and reinstalled than was possible heretofore. l

Another object of the invention is to provide a work handling apparatus comprising a conveyer and elevator mechanism by the employment of which various processes involving work handling and treatment may be more expeditiously carried out.

Other and further objects of the invention will be apparent by reference to the accompanying drawings of which there are three (3) sheets, which by way of illustration show preferred embodiments and the principles thereof and what i now consider to be the best mode in which I have contemplated applying these principles. Other embodiments of the invention embodying the same or equivalent principles may be used and structural changes may be made as desired by those skilled in the art withoutdeparting from 2 the present invention and the purview of the appended claims. I also contemplate that of the several different features of my invention, certain ones thereof may be advantageously employed in some applications separate and apart from the remainder of the features.

In the drawings:

Fig. 1 is a longitudinal sectional elevational view of a heat treating apparatus embracing the principles of the invention, with certain parts thereof illustrated diagrammatically;

Fig. 2 is a cross sectional elevational View taken in the plane of line 2 2 of Fig. 1 through the heat treating furnace embraced in such apparatus;

Fig. 3 is a fragmentary view of the structure illustrated by Fig. 1 except that Fig. 3 illustrates a modified form of conveyer and elevator mechanism employed in connection with the quenching apparatus employed in the apparatus illustrated by Fig. 1; l

Fig. 4 is a fragmentary cross sectional view taken through a portion of the heat treating furnace illustrated by Figs. 1 and 2. The viewris taken substantially in the plane of line 4-4 of Fig. 2 through the lower portion of the work con- Veying mechanism employedin the furnace;

Fig. 5 is a fragmentary cross sectional view of a portion of the conveyer and elevator mechanism illustrated by Figs. 1 and 3.I Fig. 5 is takensubstantially in the plane of lines 5-,5 in Figs. 1 and 3.

Fig. v6 is a fragmentary cross sectional view of a portion of the modied form of conveyer and elevator mechanism illustrated by Fig. 3. Fig.` 6 is taken substantially in the plane of line 6--6 of Fig. 3.

Fig. 7 is a transverse sectional View through the apparatus illustrated by Fig. 3 as the latter would appear looking downwardly in the plane of line 1 1 of Fig. 3; n

Fig. 8 is an enlarged fragmentary horizontal sectional View through the furnace taken in a plane along the line 8--8 of Fig. 1; and y y Fig. 9 is a fragmentary vertical sectional view taken along the line 9-9 of Fig. 8.

The heat treating apparatus E3' disclosed by all of the figures of the drawings comprises a heat treating' furnace II, a furnace pit I2, a quenching apparatus E3, a conveyer I4, and an elevator I6, the latter comprising a portion of the conveyer mechanism I4. The furnace I I is `provided with a furnace vestibule Il located outside the furnace I! and through which work to be processed is moved from outside the furnace 'numeral 42.

3 to the furnace and to the quenching apparatus I3. The conveyer I4 comprises a plurality of sections I8, I9 and 2I which in combination with the elevator I3 bring about and make possible such movement of the work.

The section I8 of the conveyer I4 is located on the outside of the furnace It, the section I is located within the vestibule I1 and the section 2| is located inside the furnace II. All of these conveyer sections cooperate to provide the continuous conveyer mechanism indicated at I4.

The furnace II comprises a plurality of heat insulating side walls 22, a top wall 23 and a bottom wall 24 within which heat treating chamber 26 is provided. One of the walls 22 has an opening 21 formed therein which provides an access opening through which Work being processed may be introduced to and removed from the heat treating chamber 2G. The opening 21 is provided ywith a heat insulating door 28 .for closing the opening 21 and the vcommunication between the heat treating chamber 25 and the interior of the lvestibule I1.. The vestibule I?! also is provided with an opening indicated at 29 which provides access to the interior of the vestibule I1 and a means by which work may be moved from the conveyer section I3 to the conveyer section I9 and from the section IS to the section I8. 'I'his opening likewise has door 3| by which this communication may be closed.

In the form of the invention disclosed by Fig. 1 the conveyer section I8 comprises a rectangun lar frame 32 having spaced rollers 33 rotatably mounted therein transversely with respect to the alignment of the conveyer sections I6, I9 and 2i and whereby work to be processed may be moved .to and from the vestibule I1 by rolling movement upon the rollers 33. The .conveyer section I 9 also has a similar rectangular frame 34 -hving rollers 36 similarly mounted therein and upon which work being processed ,may be moved into and out of the vestibule I1 either through Vthe opening 29 to the exterior of the furnace and the conveyer section I8 or through the opening 21 into the heat treating chamber 26 and upon the conveyer section 2|. A roller or other suitable conveyer means 31 mounted between brackets 38 secured upon an adjacent portion t of the vestibule I1 provides means for supporting the Work between the conveyer sections I2 Certain of the subject matter herein disclosed and originally claimed is now disclosed and -claimed in divisional application .Serial No. 251,-

877, led November 6, 1951, for Heat Treating Apparatus.

The work being processed may be placed directly upon the conveyer If! and moved between the various sections thereof or the Werl; may be Aplaced in work containers such as those illustrated by the numeral 2 The furnace I I has heating means comprising a plurality of heating elements or tubes 4I projecting .into the chamber 26 from the upper wall 23 thereof along opposite side walls thereof and positioned on opposite sides of the conveyer section 2! in such manner as to provide therebetween a work proc essing compartment indicated in Fig. 2 by the These heating elements or tubes 4| may be of any type of heating means that may be employed in heat treating work and may be located in the furnace in any desired manner. For example, the heating elements 4I may be U-shaped tubes such as those disclosed in my copending application for United States Patent for Heat Treating Furnace, Serial No. 670,436, filed May 17, 1946, these tubes being adapted to be supplied with a combustible mixture which when burned internally thereof heats the exterior surface thereof and from such surface the heat is transferred to the work both by radiation and convection. These tubes also are constructed in such manner as to form a gaseous fluid internally thereof and this uid is supplied to the heat treating chamber 26 and provides the circulating medium within such chamber by which heat is transferred to the work by convection. Such circulating medium, howcver, may be supplied in any other manner or may be any other kind of circulating medium which it may be desirable to employ in the process of heat treating work. However, the furnace illustrated is of the controlled gas atmosphere type so that work may be processed in the chamber 26 in a .controlled gas atmosphere and the furnace and its associated gas generating and supplying apparatus are constructed so os to main tain such atmosphere in chamber 23.

In the structure disclosed the heating elements 4I are provided with headers 43 by which the tubes are secured in openings 44 formed in the upper wall 23 of 'the furnace II. The circulating medium within the chamber 26 which is heated by the tubes or heating elements 4I adapted to be circulated between the heating elements andthe work by means of a fan or other suitable circulating means indicated by the numeral 44. The fan 44 is located within thc chamber 26 immediately above the lower wall 24 of the furnace and below the conveyer section 2I. The fan 44 is rotated by a fan shaft 46 mounted in a bearing 41 extending through and mounted within a header 48 adapted to be removably positioned in an opening 49 formed in the lower wall 24. The shaft 45 is adapted to be driven for rotating the fan 44 by any suitable means, as, for example, by an electric motor, not shown. A drive unit indicated at 5I including a belt and pulley mechanism indicated at 52 may be employed for the purpose of driving shaft 46 as a result of the operation of the motor or other means referred to. When the circulo*- ing means or fan 44 is rotated Within the heat treating chamber 26, it will circulate the circulating medium contained therein upwardly around the tubes 4I and downwardly across the Work supported upon the conveyer section 2|.

The conveyer or conveyer section ZI may be any type of mechanism suitable for moving work into and out of a furnace, although preferably the conveyer 2l comprises a frame having a plurality of spaced rails indicated at 53. (See Figs. 1, 2 and 8.) These rails, which are adapd to support the work being processed within the chamber 26 and to permit the slidable movement of such work upon the rails when the work is moved into and out of the chamber, extend -across'the opening 21 and across the chamber 26 from front to rear thereof. The rails 53 are supported at the front of the furnace upon the bottom wall of the opening 21 and at the rear thereof the frame is supported upon ledges indicated at 54 at the back wall of the furnace. The outside rails 53 of the conveyer section 2I frame may be supported intermediate their ends upon ledges 54a. Enough of the rails 53 may be employed to provide any desired number of parallel guideways for supporting work. In the structure A53 and channels 58.

shown by the drawings four of the rails 53 are provided forming guideways 56 and 51 and in which are located channels 58 which are supported between the rails 53. Transversely disposed cross frame members 59 interconnect rails The channels 58 open upwardly to provide troughs for receiving worms or screws 6| the peripheral surfaces of which rest upon the interiors of the channels 58, thereby supporting the screws for rotational movement therein. Troughs 58 are adapted to hold a suitable lubricant for the screws 6I, such as powdered graphite or mica.

Each screw 6| is provided with drive shaft extension portion 62 arranged in a reduced extension of trough 58 and which projects out of the furnace through openings formed in the rear wall where the shafts are provided with drive gears 63, each operatively associated with a drive worm 64 on the drive shaft 64a of a reversible motor driven driving mechanism indicated at 66. The driving mechanism 66 is secured in position upon the rear wall of the furnace upon a bracket indicated at 68. The driving mechanism 66, except forthe electric motor thereof. is enclosed in a suitable gas-tight housing 66a at the back ofthe furnace, the drive shaft 64a having a seal 66h between it and the housing wall where shaft 64a extends therethrough. Radial and thrust bearings 64b for shaft 64a and 62a for shafts 62 are arranged within such housing, the bearings 52a being supported to'have a limited radial floating movement to provide for shifting of screws 6| due to expansion and contraction of the supporting structure thereof.

The gears 63 and driving mechanism 66 are so arranged that when the driving motor is rotated in one direction the two screws 6| will simultaneously rotate in the channels 68 in the same direction, and when the motor is rotated in the opposite direction the screws 6| will likewise rotate in the opposite direction. It will be observed that -the diameters of the screws 6| are such that the thre-ads of the screws project above the channels 58 Where successive portions of the screw threads project between transverse supports 1| forming a part of the, base portions 12 of the work containers 39. Two of these work containers are disclosed in Figs. l, 2, 8 and 9 as being disposed upon each of the guideways 55 and 51 formed between the rails 53. The bases 12 also are provided with pairs of spaced longitudinal supports 13 between which are other integral longitudinal supports 14. The transverse supports 1| are notched at the ends as is indicated at 15 (Figs. 2 and 5) to provide for the extension of the supports 1| downwardly between the guides formed by the upper extremities of the rails 53.

The transverse supports 1| at the ends of the trays 12 of containers 39 have inwardly offset portions 1|a at the center thereof as shown in Fig. 8 so that the minimum distance between the screw engaging portions of adiacent trays 12 (if the containers 39 were abutting each other) is slightly less than the distance between adjacent threads of screw 6| so that each tray 12 must be individually moved by screw 6| as Idistinguished from screw 6| moving one tray 12 and such tray 12 pushing the next adjacent tray. This arrangement is provided to prevent excess loading of the threads of screw 6| and of the screw engaging portions of trays 12.

The two longitudinal supports 13 which are formed integrally at opposite ends of the trans-,-

verse supports 1| are narrower than the transverse supports 1| and are spaced from one another to such an extent that when :the containers 39 are disposed upon the guideways 56 or 51 the supports 13 are maintained by the notches 15 in such position as to slidably engage the upper edges of the rails 53. The longitudinal supports 14 are of the same thickness as the transverse support 1| and are spaced inwardly from the supports 13 beyond the notches 15. Another longitudinal support indicated by the numeral 16 is disposed midway between the pairs of supports 13 and 14 for each container base 12. These latter supports extend only along the upper edge portions of the bases 12 so as to provide space therebeneath for receiving the peripheral portions of the screws 6| within the bases 12 and between the transverse supports 1| thereof.

The containers 39 also comprise metallic side walls 11 having flanges 19 around the lower edges thereof which are adapted to be seated in notches formed in the upper surfaces of the transverse members 1| immediately inside the longitudinal members 13. Grills 19 formed of wireor other suitable material are disposed inside the walls 11 in such position as to rest against the upper surfaces of the members comprising the bases 12. The grills 19 provide .means for supporting work within the containers 39 in such manner that the circulating medium in the chamber 26 may be circulated downwardly over the work, through the various openings in the grills 19 and the bases 12 and between the rails 53 in response to the operation of the fan 44. In order to di-rect the circulating medium toward the central portion of t'he fan 44 there is secured upon and to the underside of the conveyer section 2| frame a plate or baffle 8| having a central opening above and in line with the fan 44.

Referring particularly to Fig. 5, it will be noted that the section I9 of the conveyer |l|l which is located within the vestibule |1 also is formed in such manner as to provide a continuation of the pairs of guideways 56 and 51 for guiding the bases 12 of the containers 39 thereacross. The conveyer section 9 has rails 82 extending transversely across and forming a part of the rectangular frame 34 for providing the guideways 56 and 51. Also extending across the rectangular frame 34 between each pair of the rail-.s 82 are channel members 83. Between adjacent sides of the channels 83 and the rails 82 are rotatably mounted the rollers 35 on which the bottom surfaces of the work baskets or containers 39 rest when the work is transported across or supported upon the conveyer section i9. The notches15 in the bases 12 provide transverse guide means for maintaining the bases 12 between the upper extremities of the rails 82. However, the rollers 36 are located in such a position that the transverse supports 1| do not slidably engage the upper surfaces of the rails 82 when the work containers are supported upon the convey/er section I9, as these longitudinal supports 1| do slidably engage the rails 53 when the work containers are supported upon the conveyor section 2|.

In the structure disclosed by Fig. 1 theaconveyer section i8 located outside the vestibule |1 is constructed with a i rame 32 with transverse rails and channels like the rails 82 and channels 83 illustrated by Fig. 5 and between which. therollers 33 are mounted for supporting the containers 39.

The elevator 6 by which the conveyer sections I8 and |9 are supported comprises a pair .of end frames 84 each consisting of a transverse channel member 88, a vertical channel member 8l secured at one end of the member a and a, supporting plate 80 secured at the opposite end thereof. The plates 80 are secured to opposite ends of the' frame '32 of the conveyer vsection I8 while the channel members 'l are secured to the opposite ends of the frame 3s of the Yconveyer section I8. A frame member 88 projects across the space between the end trames 85 between the conveyer 'sections I8 and I '9 and is secured rigidly into the end frames 84 at the opposite ends therew of. 'Guide members 89 disposed vertically with respect to the end frames 84 and midway between the conveyer sections I8 and I9 provide means for maintaining the conveyer sections I8 and |9 in the same relative position when the elevator I8 is moved upwardly and downwardly, one guide 89 being at each side of said elevator I8.

The vestibule I`| is provided with an opening SI across the lower extremity thereof and directly beneath the conveyer section |9 when the latter is in its upper position. The opening 9| is so ar ranged that when the elevator I6 is moved downwardly the conveyer section I8 will pass through the opening 9| and .into the space therebeneath. Disposed about the elevator |i and having an upper open end located just beneath the normal upper operational level of the various sections ol the conveyer I 4 is the quenching tank I3 in which the normal level of the quenching oil or other suitable fluid is indicated hy the numeral 92. The location of the opening 8| in the lower port of the vestibule I1 is such that the quenching oil level indicated at 82 is preferably above the opening 9|.. The lower end of the quenching tank I3 is disposed below the level of a steel plate or other suitable door indicated at 93 and extends into 4a pit 94 forming a part of and communicating with the pit I2 beneath the furnace I I. Within the pit 94 the tank I3 is provided with a drive opening 96 closed by a bearing and head member 91 through which projects the drive shaft 98 of a quenching iluid circulating propeller 99. The outer end of the shaft 98 is provided with a driving .pulley and ybelt unit indicated at |DI adapted to be driven by a motor not shown but preferably located within the pit 94. The propeller 99 is positioned in an outlet portion I 82 of a quenching fluid circulating tank or means |03, the upper end of which is provided with an inlet opening |04 adapted to register with the frame 34 of the conveyer section I9 when the elevator I6 is lowered sufliciently to permit the frame 34 to seat on the upper rim of the tank |03 around opening' I 84. The end frames 84 of the elevator I6 move downwardly within tank I3 and on opposite sides of the ends of the tank |83 as is indicated by the dot and dash lines indicated at |06 in the structure illustrated by Fig. l, Inside the tank |93 and just beneath the opening |94 is a finned coil indicated at |01 through which water or other suitable cooling fluid is adapted to be circulated to and from conduits |88.

It will be apparent from Fig. 1 that when the elevator `I 6 is lowered into the dotted line position in which the space enclosed by frame 34 registers with the opening |04 and frame 34 is seated on the rim around .opening |04 that the quenching fluid in the 'tank I3 will be circulated downwardly over the work supported by theconveyer section I9, across the cooling coil |01 and outwardly through the outlet |82, when the propeller 99 is rotated in such direction as to discharge quenching fluid from the circulating tank |83 into the 'quenching tank I3 through the outlet |02. Since the outer lower frame members of tray I2 of 8 basket 39 have a close tit with frame 34 as shown in Fig. 5, as previously described, it will be apparent that the quenching lluid will be positively circulated through basket 39 and over the work contained therein at such time.

The elevator I6 is adapted to be moved upwardly and downwardly for moving the conveyer sections I8 and I9 between the upper normal operational level of the conveyer sections I8 and I9 and their lower position by chains or cables |09 secured at one end of the supporting member or beam 88. The chains are adapted to be wound around pulleys II I secured at opposite ends of a. shaft ||2 mounted in bearings II3 secured by bolts I I4 to ya supporting frame |I positioned upon an upper wall I of the vestibule The shaft ||2 is adapted to be driven alternately in opposite directions by a chain I I8 operatively associated with a. sprocket wheel ||8 mounted on the shaft |I2 and with a second sprocket wheel or pulley |2I mounted upon a. drive shaft |22 of a reversible motor drive mechauism indicated at |23. The drive mechanism |23 is supported upon a frame |24 located above the frame ||6 and which in turn is supported by the upper ends of guide members 89 which project out or" the upper end of the quenching tank I3 and along the front of the vestibule on the opposite sides of the door 3 I.

When the reversible drive mechanism |23 is operated so as to drive the shaft |22 in opposite directions the conveyer sections I8 and I9 will be moved upwardly or downwardly between the aforesaid normal operating and quenching positions respectively.

The vestibule door 3| is also provided with a cable or chain indicated at |26 which extends about a pulley |21 mounted in a bearing |28 secured to the frame |24 and the opposite end of which cable supports a counterweight |29. The door 3| may be opened or closed merely by taking hold of the end of the cable |26 supporting the counterweight |29 and lifting upwardly or pushing downwardly. The door 3| is provided with a vent indicated at |3I adapted to exhaust surplus circulating fluid from the interior of the vestibule I1. If a combustible circulating iluid or medium is employed, then the excess circulating fluid may be burned by lighting a match adjacent the vent I3 I.

The door 28 also may be opened and closed with respect to the opening 2l leading to the heat treating chamber 26 by the operation of a cable |32 secured at one end to the door and wound around a pulley indicated at |33 which is mounted upon a shaft |34 secured in frame members not shown but located in an upwardly extending part |36 of the vestibule I'I. The shaft I 34 is driven in opposite directions for opening and closing the door 28 by chain |37 operatively associated with a sprocket wheel not shown but located upon vthe end of the shaft |34 behind the pulley |33 and another sprocket wheel, also not shown, but mounted upon the drive shaft of a second motor driven reversible drive unit identical to the drive unit |23 and located by the side of drive unit |23 upon the frame |24. The door 28 also is provided with a vent indicated at |38 for the purpose of allowing surplus circulating fluid to escape from the heat treating chamber 28 into the vestibule Assuming the heat treating chamber 26 to be lled with the desired circulating medium and to be heated by the heating elements 4| to the desired temperature for heat treating the work deveyer section I8.

vupon the cable |26 and thereafter the two work containers containing the work to be heat treated may be rolled into the vestibule I1 through the opening 29 and upon the conveyer 'section I9 merely by pushing on the work containers and moving the containers in the aligned guideways 56 and 51. On the conveyer sections I8 and I9 the work containers will be supported upon the rollers 33 and 36 and will be guided between the rails 82 of each of the conveyer sections by the notches 15.

Assuming the proper oneof the reversible drive units |23 to have been operated for opening the door 28, the containers 39 may continue to move across the conveyer section I9 upon the rollers 31 and into contact with the screws 6I and the Aguide rails 53 forming the guideways 56 and 51 within the conveyer section 2|. By operating the motor drive unit B6 the screws 6I now may be rotated in such manner that the containers 39 will be pulled into the heat treating compartment 26 by the engagement of the upper part of the screws 6| with the transverse supports 1| forming a portion of the base 12 of each container. During such movement of the containers 39 in response to the rotation of the screws 6|, the containers will be slidably supported upon the upper edges of the rails 53 and the longitudinal support members 13. When the containers 39 have arrived at an operative position in the furnace chamber 29 the operation of the drive motor 66 may be discontinued, such as by means of an automatic stopping mechanism (not shown) associated with motor drive unit 66, and thereafter the work in the containers 39 may be heat treated by closing the doors 3| and 28 and practicing the desired heat treating process.

As is illustrated by Fig. 1, four or any desired number of heat treating containers may be positioned in the furnace at one time depending upon the size of the containers and the furnace. This may be done by simply lining up several of the `containers 39 in each of the guideways 56 and 51 'and upon the conveyer sections I8 and I9 and the roller 31 before starting the operation of the screws l6 I. Thereafter when the screws 6I engage the transverse supports of the first pair of containers 39, it is necessary only to push the remaining containers upon the rollers 33, 36 and 31 in such manner as to cause these containers to rfollow the rst pair of containers and thereafter all of the containers will be moved inwardly with respect to the heat treating chamber 26 upon the conveyer section 2|.

Referring particularly to Fig. 1 and after the work has been heated to the desired extent within the chamber 26, the heat treating process may be continued by operating the motor drive unit |69 in such manner as to reverse the rotation of the screws 6 I. Assuming the door 28 to have been opened by operation of one of the drive units |23, the first pair of the work containers 39 will be pushed along the rails 53 by operation of the screws 6| and outwardly into the vestibule I1. When this pair of containers has been released from the screws the operation of the drive unit |66 should be discontinued and the first pair of containers 39 may then be pulled upon rthe rollers 31 and 36 into a position in which the bottoms of the containers 39 register with the 10 frame 34 and the middle pair of the rails 82 located in the conveyer section I9. Thereafter the properV one, of the drive units |23 is operated in suchmanner as to lower the conveyer sections |8 and I9 out of the upper normal operating position and into such position that the frame 34 of the conveyer section I9 will register withthe `opening |04 formed in the upper end ofthe circulating tank |03. During the downward movement of the containers 39 the work will first engage the quenching fluid, the level of whichis indicated at 92, inside the vestibule I1 andV above the outlet opening 9| thereof. Such engagement may cause some evaporation of the quenching uid but such evaporation will result in evaporated quenching fluid rising into the vertibule I1 where the same will be discharged from the vent |3| and burned in the excess circulating medium which may be escaping from such vent. The drive unit |23 employed in operating the elevator I6, however, should be of such size, capacity and speed that it will lower the elevator somewhat rapidly, and under such circumstances only a relatively small amount of quenching fluid will be evaporated during the downward movement of the containers 39`prior to the time when the frame 34 registers with the opening |04 in the circulating tank |03.

yAssuming the propeller 99 to be rotating-in such manner as to discharge quenching fluid from thetank |03 through the opening |02, itwill be at once apparent that there will .have been a downward movement. of the quenching fluid through the opening |04 during the time when the containers 39` were being lowered into the quenching tank by the operation of the elevator I6. Such downward movement of the quenching fluid will tend to trap evaporated quenching fluid in the work and to carry such evaporated quenching fluid downwardly with the work until Athe frame 36 registers with the opening |04. Thereafter the quenching iuid will continue to circulate downwardly through the containers 39 and over the cooling coils |01, and hence the trapped and evaporated quenching fluid will tend to be carried downwardly into the tank |03 where it will be cooled and condensed upon the cooling coils |01. Thereafter the circulation' of quenching fluid will continue outwardly through the opening |02 into the tank I3 and downwardly over the work within the containers 39, thereafter to be cooled for recirculation over the work by the operation of the cooling coils |01. i f

Notwithstanding the fact that the tank. I3 is open to the atmosphere in the region around the conveyer section I8, there will be little orno escape of evaporated quenching fluid to theatmosphere. Such escape to the atmosphere of evaporated quenching fluid is prevented by the fact that the opening 9| is below the quenching fluid level indicated at 92 and consequently any evaporated quenching fluid either rises outwardly into the interior of the vestibule I1 or is carried downwardly into contact with the cooling coils |01 .with the .pair of containers positioned on the conveyer section I|.9. The pair .of containers by this means may be moved withinthe tank I3 beneath the quenching fluid level therein into a DOsition on the .conveyer section I8. By reversing the operation of the elevator driving unit |33, .theelevator .I5 may then be raised .into a position -in which the conveyer sections I8 and I9 are in normal .position in alignment with .the conveyer section 2| and the Work containers 39 then may be -removed from the conveyer I8. It will be noted that during the previously described Iquenching operation the door 3| was allowed to remainin closed position.

Thereafter ,the operation of the motor drive :unit .6 maybe continued in such manner as to ,push another `pair of the .containers 39 from the .conveyer section 2| .to the conveyer section I9, and the .quenching operation previously described maybe repeated .until all of the containers are removed from .the furnace and the quenching .operation has .been completed for all of .the work `in .all `of the containers.

` 'In the structure disclosed by Figs. 3, 6 and '7 .there is illustrated a modified form of the conneyer mechanism I4 in .which the conveyer section I8 located .outside the .vestibule Il' comprises conveyer means or rollers |39 positioned at an angle with respect to and intersecting other rollers .|40 forming a part of conveyer means |4| which serves as a part of and an extension Aof conveyer section |.8 and at the same time as a continuation .of the main .conveyer system I4. The rollers |40 are mounted transversely .with respect Alio and upon rails |42 .extending along and past the front .of :the vestibule I'I. The conveyer |4| may .extend in .either .direction from the vestibule to machines where work is being done that may require heat treatment or .to other furnaces similer .to the furnace where 'heat treating work may be in process and which process it may be desirable to .complete .by .bringing the work down .the conveyer `|.4 where .the quenching operation .of .the process may be .carried out in quenching tank Il. The work containers 39 when moved .upon the rollers :|40 will move in parallel relation to .the rails |.42 and transversely with respect `to the .operational position of .the rollers |39.

AIn .order .to be able :to move work containers from rollers .|40 to rollers |39 .and from rollers Il! .to rollers |40, the rollers |39 are mounted upon .bars .|43 .positioned vbetween the rollers |40 and supported on channels .|44 which in turn are spaced Vbeneath the rollers |40 .and upon Athe lupper .edge ,surfaces of which the bars |43 are rigidly secured. The channels |44 are in turn supported at .Opposite Vends by vertically disposed channels |46 which constitute a part of the elevater .I6 yand correspond to the end supports 81 mnliyed in Vthe structure disclosed :by Fig. 1. 'libe remainder of the structure disclosed by Figs. 3, 6 and 7 is identical to that .disclosed by Fig. 1,

corresponding reference numerals are accordingly applied thereto. It will beobserved that the structure disclosed by Figs. 6 and 7 may be employed for servicing- .Several furnaces such as that indicated by the numeral II with one quenching tank apparatus such as that indicated b y -the numeral I3.

In operation the structure disclosed by Figs. 6 and 7 ls identical ,to .that ydisclosed by Fig. 1 except Awith regard to the movement of the work containers l39 within the tank I3. When the containers .3 9 have` been positioned within the tank I3 ,tu such position as to register with .the .open- .ing |04 .inthe circulating tank |03 and after the work has been cooled to the desired tempera.- ture, the containers v,cannot be moved Vacross 'the quenching tank from one ,conveyer section to another. It is necessary in the structure vdisclosed by Fig. '7 to .operate ythe elevator in such ma-nner as to move the containers back into the vestibule Il, and then `after opening the door l3| the containers may be pulled from the conveyer section I9 to the conveyer section I8. By again operating the elevator so as to move the rollers 33 downwardly a short distance the containers .then will rest upon the rollers |40 and .then may be moved in either direction along the conveyor 4|. Work to be processed also may be brought from other furnaces along the conveyer I4I, in which event the containers are stopped upon the conveyer I3 in such position as to register with the rollers |39. Thereafter by raising the elevator I6 slightly, the work may vbe lsupported upon the roller |39, and then by opening the door 3| the work containers may be rolled through the opening 39 and upon the conveyer section I9 to be thereprocessed as previously described.

Referring again to Fig. l, it will be noted that the bearing l4l has secured thereto a webbed plate |48 on which the header 48 is supported and which is adapted to be removably secured to .the lower wall 24 by screws indicated at |49. The plate |48 also has bars |5| secured at the upper ends thereto and at lthe lower Yends the bars |5| are attached to a rectangularly shaped frame |52. The frame |52 has brackets |53 secured at the corners thereof Within which are rotatably mounted wheels or rollers |.54. Cables or chains |58 are each secured at one end to one corner of the frame |52 and a pair of the cables at one end of the frame are .adapted to `extend over rollers |57 and thence across the bottom of the furnace where all of the cables are Wound upon rollers or drums |50. The rollers |58 are provided with an operating shaft |59 one end of which is provided with a `crank IBI extending beyond the side Walls of the furnace I and in such position as to he manually .operable for rotating the roller |58. The rollers' |51 and |58 are mounted between pairs of channels extending across the bottom wall 24 of the furnace, these being suitably bent to accommodate the difference in width of the rollers |51 and |58.

It will be apparent that when the screws |49 are removed it is possible to remove the fan 44 through the opening 49 by unwinding the cables ,|56 from the roller |58. In this manner the entire .circulating means can be lowered to any desiredextent below the furnace and until the frame |52 supports the entire structure at the bottom of the 'pit I2 upon vthe rollers |54. Thereafter by releasing the cables |06 from the frame I 52 it is possible to move the fan structure laterally within the pit I2 until the structure is directly beneath a door 95 which is formed in a steel plate floor 93. After opening the door 95 it is possible to remove the circulating means or fan strucl ture from the pit in any suitable manner as by the employment of a portable crane or hoist, not shown, After the fan has been repaired it is possible to replace the fan in operative position within the furnace by reversing rthe sequence of operations previously described.

While I have illustrated and described preferrea .embodiments 0f my invention.. itis understood that these are capable o f modification, and I therefore -do not wish to. bev limited ,to the pre-.-y cise details set forth but desire .to avail -myseliI .of

such changes and alterations as fall within the purview of the following claims.

I claim:

1. A heat treating apparatus useful in the art of heat treating metal work comprising an eievator, quenching means for work associated with said elevator, said quenching means comprising a tank of quenching fluid beneath the normal upper position of said elevator, said tank having circulating means therein beneath the level oi said quenching fluid, said elevator being provided with drive means for moving said elevator into operative position with respect to said circulating means, said circulating means being operable for circulating said quenching fluid over said work and in intimate contact therewith when said elevator is in operative position with respect to said circulating means, said elevator comprising a frame adapte-d to register with an opening in said circulating means and being provided with a removable work container having side walls adapted to register with said frame and a perforated bottom wall within said side walls, said frame and said side walls when in registry being adapted to direct said quenching fluid over said work during the operation of said circulating means, and to prevent circulation of said quenching fluid without passing directly in contact with said work.

2. A heat treating apparatus useful in the art of heat treating metal work comprising a plurality of heat insulating walls defining a batch type heat treating chamber, one of said walls having a vertically extending opening providing access to said chamber, a door for closing said opening, a conveyor extending within said opening and across said chamber for supporting work being processed Within said chamber and for conveying said work within and without said chamber, said conveyor having a section outside said chamber comprising an elevator, a vestibule surrounding said section and communicating with said chamber through said access opening and having an access opening formed therein, a door for closing said access opening to said vestibule, said openings to said vestibule and said chamber being in line, said vestibule having a quenching opening formed therein beneath said elevator, and a quenching tank beneath said vestibule, said quenching tank having an upper open end surrounding a lower portion of said vestibule and having quenching iluid therein at a level above said quenching opening in said vestibule whereby work on said elevator may be lowered from said vestibule into and out of said quenching tank.

3. A heat treating apparatus useful in the art of heat treating metal work comprising a plurality of heat insulating walls dening a batch type heat treating furnace chamber, one of said walls having a vertically extending opening providing access to said chamber, a door for closing said opening, a Work conveyor extending horizontally through said opening and across said chamber for moving said work in and out of said chamber, said conveyor having a section outside said chamber opening comprising an elevator, a vestibule surrounding said elevator and communicating with said chamber through said opening therein and having an access opening for work formed therein in line with said opening in said furnace chamber, said vestibule having a quenching opening formed therein beneath said elevator inside said vestibule, a quenching tank, circulating means in said quenching tank arranged positively to circulate quenching liquid in a predetermined path, said elevator being provided with reversible drive means for lowering said elevator and the work supported thereonk into said tank, said elevator when lowered into said tank positioning work thereon relative to said circulating means so that quenching liquid circulated thereby in its flow through its path must circulate in intimate contact with the work on said elevator, and a means operatively positioned relative to said elevator to receive work therefrom when said elevator is in its lower position in said tank so that work may be removed from said elevator while in said quenching tank.

4. A treating apparatus for metal work comprising a work conveyor having a pair of sections comprising an elevator, a vestibule surrounding one of said sections and having an access opening formed therein between and in line with said pair of sections, said sections being adapted at one elevation of said elevator to support work for movement into and out of said vestibule through said access opening, said vestibule having a quenching opening formed therein beneath said conveyor section inside said vestibule, and a quenching tank beneath said vestibule, said quenching tank having an upper open end surrounding and projecting above the lower portion of said vestibule and having a quenching fluid level therein above said quenching opening in said vestibule, alternative conveyor means adapted to conduct work along a path intersecting said conveyor section outside of said vestibule, positioning of said elevator at an elevation below said one elevation being adapted to deposit the work on said outside conveyor section at the intersection of said paths from said outside conveyor section to said alternative conveyor means.

JOHN A. DOW.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 524,409 Wright Aug. 14, 1894 737,079 Chase Aug. 25, 1903 786,365 Kenworthy Apr. 4, 1905 820,619 Bickford May 15, 1906 955,989 Pederson Apr. 26, 1910 1,335,912 Olson Apr. 6, 1920 1,359,936 Barth Nov. 23, 1920 1,438,680 Barron Dec. 12, 1922 1,697,894 Wright Jan. 8, 1929 1,702,524 schoonmaker Feb. 19, 1929 1,934,916 Dies Nov. 14, 1933 1,960,339 Howard May 29, 1934 1,969,708 Betke Aug. 7, 1934 1,979,108 Ipsen Oct. 30, 1934 2,061,775 Panos et al. Nov. 24,1936 2,149,883 De Coriolis Mar. 7, 1939 2,223,603 Darrah Dec. 3, 1940 2,352,709 Haase July 4, 1944 FOREIGN PATENTS Number Country Date 294,612 Germany Feb. 18, 1916 239,412 Switzerland Jan. 3, 1946 

